Principal Project Manager

Assystem is an international company with one mission: accelerate the energy transition around the world.

Every day, our 7,500 switchers located in 12 countries (Europe, Middle East, Pacific Asia & Africa) connect their six thousand billion neurons to tackle the task of the century: switching to low-carbon energy.

We are a collective committed to the actors who are making the energy switch. Sharing our knowledge, expertise and values allows us to innovate and think differently about the energy transition.

Drawing on more than 55 years' experience in highly regulated sectors subject to strict security and safety requirements, we provide our customers with engineering and project management services, as well as digital services and solutions to optimize the performance of complex infrastructure projects throughout their life cycle. The Group is currently ranked third in the world for nuclear engineering.

To ensure a viable, efficient, and reliable energy future for all

At Assystem, we’re driving forward some of the UK’s most complex and high-profile Nuclear Defence programmes – and we’re looking for a Principal Project Manager (PPM) who’s ready to take the lead.

This is more than project management. It’s about influencing strategic outcomes, shaping capability across the business, and ensuring we deliver mission-critical projects with precision, accountability, and innovation.

As a senior leader in our Defence business, you’ll play a pivotal role in managing and evolving a multi-project portfolio, supporting blue-chip defence clients and aligning delivery with AEIL’s wider growth objectives.

Your missions:

🛠 Programme & Portfolio Delivery

• Oversee a large volume of concurrent projects with full lifecycle responsibility
• Lead governance reporting on performance metrics – safety, time, cost, quality, client satisfaction

👥 Leadership & People Development

• Inspire, lead, and line manage project and PMO staff, helping them reach their full potential
• Provide coaching, direction, and mentoring to improve delivery capability across the function

📈 Strategic & Commercial Insight

• Contribute to budget planning, business case development, and financial performance cycles
• Identify and embed opportunities for innovation and continuous improvement
• Lead by example in client relationship management and commercial negotiation

Why join the community of Switchers?

As one of the Top 3 Nuclear Engineering companies in the world, Assystem offer a competitive benefits package which includes:

💥25 days of annual leave + bank holidays

💥8% company pension contributions

💥Healthcare cash-plan to get money back on dental, medical, physical care

💥Employee assistance programme including 24/7 access to free mental health support, virtual gym classes and more

💥Get professional and industry membership fees paid for.

Essential Qualifications/Skills to be successful:

✔ Proven track record of delivering large, complex, or high-volume projects in structured environments

✔ Strong leadership skills with the ability to guide multi-disciplinary, cross-functional, and virtual teams

✔ Excellent communicator and influencer at all levels, including executive stakeholders and clients

✔ Chartered status (or working towards) in Project or Engineering disciplines

✔ In-depth knowledge of risk, budget management, cost control, scheduling, and reporting tools

✔ Expertise in change management, contract management, and strategic delivery frameworks

✔ Commercially astute with a pragmatic approach to decision-making and solution delivery

Desirable qualifications/skills to be successful

➕Experience in the Nuclear Defence sector or other regulated industries

➕ Familiarity with the NEC4 contract suite and delivery under Framework or JV arrangements

➕Technical engineering understanding (Mechanical, Electrical, EC&I)

➕ Previous involvement in developing project bids or client proposals

🔎 If you’re a strategic thinker, a strong leader, and a results-driven project professional ready to shape the future of defence delivery — we’d love to hear from you.

Ideally Derby or Bristol office based but other AEIL UK offices an option

Hybrid working

Sole UK National preferred, BPSS to start but SC clearance required

Permanent staff role

We are committed to equal treatment of candidates and promote, as well as foster all forms of diversity within our company. We believe that bringing together people with different backgrounds and perspectives is essential for creating innovative and impactful solutions. Skills, talent, and our people’s ability to dare are the only things that matter !. Bring your unique contributions and help us shape the future.